Volume 58 (2008) Issue: 2008 No#5-6

Efficacy of the presynch-ovsynch program on some reproductive parameters in postpartum dairy cows

Author(s): Akoz M, Aydin I, Ali Dinc D

Keywords:cow, presynch-ovsynch, reproductive parameters

In this study, the aim was to evaluate the presynch-ovsynch
protocol on the intervals from calving to first insemination, calving to
pregnancy, calving to calving in postpartum lactating cows. Lactating
Holstein cows (n=104, 3-5 years old, 450-500 kg BW, 27±3 kg/day
average milk yield) were enrolled in the study 26-41 days postpartum.
Fifty of them were taken as the control group and 54 of them were the
treated experimental group. The control group was not treated and the
cows in estrus were inseminated. In the treated group the cows were
injected with two PGF2 for presynchronization twice at every 14 days.
Fourteen days after the second PGF2, ovsynch protocol was initiated
(GnRH, day 0; PGF2, day 7; GnRH, day 9) and cows were inseminated
12-16 hours after second GnRH injection. Following AI, cows returning
to estrus were inseminated at detected heat. Pregnancy diagnosis was
performed by ultrasonography at 33-38 days after AI. Calving to first AI
(days), calving to pregnancy (day), the number of AI per pregnancy,
calving interval (days) for control cows were 96.08±8.20, 147.58±9.95,
2.19±0.20 and 430.50±10.90 and for the treated group 70.13±1.13,
101.76±5.70, 1.85±0.12 and 386.80±5.70, respectively. Compared to
the control group, calving to first AI interval was shorter by 26 days,
calving to pregnancy interval by 46 days and the calving interval by 44
days (p<0.001). Number of AI per pregnancy decreased numerically
from 2.19 to 1.85. Pregnancy rates for the first AI was 47% for the control
and 43% for the treated cows (p>0.05).
As a result, by using the presynch-ovsynch protocol, the need for
estrus detection was eliminated and inseminations were performed at a
fixed time. Therefore, calving to first AI, calving to pregnancy, calving
intervals and the number of AI per pregnancy were improved to the
benefit of the farm.